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Dragon Boat Canada


IDBF


Canoe Kayak Canada

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[Guts and Glory]

All other things equal, what does everyone think is the difference in time between a BUK and a Gemini is?   Maybe 5 to 7 seconds?  Has anyone taken a GPS on board to compare peak speeds between the two?

I've also noticed that the Gemini's tend to sit a lot lower in the water - any know what the difference in weight between the two boats are?

Thanks!

[mandachan]

This is all just a theory...

The Gemini and BUK are both the same length (I think it's the standard 30ft?) and the same weight (approx 700-800lbs unloaded... don't quote me)

The BUKs feel lighter and faster because they have bigger air tanks in the bow and stern so they sit higher on the water. Geminis have a smaller one and sit deeper in the water. I also think that in general if you look at both boats from a profile view, the BUK looks slightly stern heavy and the Gemini looks the opposite (which is a bad thing for speed, like chronically nose-diving into the water).

The Gemini's seating arrangement had been retrofitted, at Dragonzone at least, so that there are 10 seats. The boat wasn't meant for this and feels cramped in the front and back... so hip-drive is sacrificed and the boat doesn't get as much movement and power. The BUKs are wider and allows for that hip-drive. Also, it's spacious enough to allow for the decent lean that a Gemini can't provide, again allowing more power.

Methinks we should sneak into DZ and unleash all the Geminis into the ocean and let them drift away.

Disclaimer: I'm actually a noob and I know nothing about dragonboat.

[Illuminate]

I was actually looking at time differences today from Sunday's DZ Regatta, the difference can be up to 10 seconds

[LittleSchrodinger]

I also know nothing about the technical details for Geminis and BUKs, and this is just my own uninformed opinion.

I thought the size of air in the hull of the boats don't affect how they sit in the water? I thought it's about the shape of the hulls if they're the same weight, going with the basic (volume of water displaced by hull) x (mass of water) = (buoyant force)? Unless BUKs are secretly filled with helium or hydrogen. I don't actually find Gems to be that cramped being a short guy, but I much prefer the footholds on a BUK. The Gems may sit lower in the water, but the seats themselves are higher off the bottom of the boat than BUK and the footholds a bit more forward, so I find it pretty hard to get my knees in a good driving angle without going into a near-kneel. And my god, despite the retrofitting, it's still a pain to grind my hip against the side of the boat. I'm afraid I'm going to skin the side of my legs on those metal edges sticking out of the side if I'm not careful.

Generally speaking I put the time differences between the two boats at just three seconds, significant but not that much.

[puppy]

http://www.dragonboatwest.net/index.php?topic=1127.15

[StrokeItHard]

I heard the difference can be minutes.


In all seriousness, I heard the difference is 3-4 seconds for the same crew.

[mappingguy]

DZ really should fix the inside of the geminis.  I know several people who skinned their outside leg on the edges of the old the seat positions.   

[mandachan]

DZ really should fix the inside of the geminis.  I know several people who skinned their outside leg on the edges of the old the seat positions.   

It's like a badge of honour isn't it?
"I paddle out of Dragonzone, and I paddle proud"

[rb]

I heard the difference is 3-4 seconds for the same crew.

I agree and have looked at lots of data from previous regattas. It's bit more for teams that aren't used to them, say 5 seconds, but once you figure them out you can get it down to about 3.

All boats have to be clean of course and there were some comments that it might not have been the case on the weekend. 

Tide is also a big factor in False Creek, about 5 seconds between strong tide and slack tide, or 10 seconds between strong outgoing tide and strong incoming tide. Also wind can be a couple seconds, as can start positions (not all heats start at the exact same place, as long as teams are lined up they go).

All other things being equal I would take 3 seconds off Gem times to get equivalent BuK times.

[alcanranker]

My two cents,

a. The Geminis are a bit bow heavy so don't load the big people up front.  I agree there is less air in the bow and stern thus less buoyant.  The Gemini is the same length as the Buks which is approximately 43 feet or so.
b. Geminis are more sensitive to any bad technique, dragging, weight coming in and out.  Buks are not forgiving but Geminis even less.
c.  Geminis originally had 11 seats and then they were retrofitted to have 10 seats with a bar and then retrofitted to remove the bar.  The last retrofit caused the foot braces to be at an unusual location thus the comment on being tighter but they are not there is actually more room compared to 2004.
d.  If you are a good team then 3-4 seconds is a good estimate, any bad technique just add some more seconds.
e.  Have good technique, lock yourself against the gunnel and stay out and you will be fine (as is possible).

You can make them go fast but it takes practice, have fun.

[threesea]

The amount of air in the stems of a boat has nothing to do with buoyancy.  If all things are equal but the Bucs are wider, then the actual downward pressure of the boat into the water will be less; hence they will be higher out of the water, less draft which will equate into more speed

[mandachan]

The amount of air in the stems of a boat has nothing to do with buoyancy.  If all things are equal but the Bucs are wider, then the actual downward pressure of the boat into the water will be less; hence they will be higher out of the water, less draft which will equate into more speed

That's probably it then. I know nothing about water physics as you can see... but that makes sense that it's wider so more buoyant.

My two cents,

a. The Geminis are a bit bow heavy so don't load the big people up front.  I agree there is less air in the bow and stern thus less buoyant.  The Gemini is the same length as the Buks which is approximately 43 feet or so.
b. Geminis are more sensitive to any bad technique, dragging, weight coming in and out.  Buks are not forgiving but Geminis even less.
c.  Geminis originally had 11 seats and then they were retrofitted to have 10 seats with a bar and then retrofitted to remove the bar.  The last retrofit caused the foot braces to be at an unusual location thus the comment on being tighter but they are not there is actually more room compared to 2004.
d.  If you are a good team then 3-4 seconds is a good estimate, any bad technique just add some more seconds.
e.  Have good technique, lock yourself against the gunnel and stay out and you will be fine (as is possible).

You can make them go fast but it takes practice, have fun.

How the hell did they fit 11 seats into that thing?!  gosh

[wanker]

DZ really should fix the inside of the geminis.  I know several people who skinned their outside leg on the edges of the old the seat positions.   

Yup, while we no longer have the telltale grey streak running down our thighs (from the old chainlink fence posts that were since removed), you can easily scrape the hell out of your outside leg depending on which seat of the Gemini you paddle in.  Spacing throughout the boat is all kinda wacky now that they removed a bench, and the relative position of the new benches to the old seat supports puts these jagged plastic hazards at different places for each paddler.  I've had nasty little gashes on my thigh, outside of my knee and part way down my calf.  They take about a week and a half to heal, at least in my case.  Let's just sink them!   

The front seat can be quite compact.  I was paddling in one just this past weekend and my seat mate tried to unscrew the little round cover on the front plate underneath where the drum sits, in order to gain a little extra space for his foot. 

That being said, the BUK's could use a little sanding and revarnishing as the top rails are getting a bit weathered.

Dunno about the real time difference but it would not surprise me to see 10 seconds added to a crew's time.  It's kinda tough to calculate based on only a single festival as I would suspect that all but the very top tier teams have bad races occasionally, not to mention wind and tidal influences plus differences between the lanes.  I know that my team put in a quicker time in a Gem compared to a BUK this weekend, but we had a couple of pretty horrid races before finally cranking out something that felt good.  It happens.